JP2006180105A - Real-time communication system, switching device, real-time communication method, and real-time communication program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve actual use efficiency of resources by lightening a load on equipment. <P>SOLUTION: The real-time communication system is equipped with a switching device which relays call control signals transferred between terminals and an inter-terminal real-time signals between a 1st interface side and a 2nd interface side, and the switching device includes a 1st-side real-time signal reception portion, a 2nd-side real-time signal reception portion, a state display portion, a holding-tone transmission portion, and a switch portion which does not supply an inter-terminal real-time signal delivered from a 2nd communication terminal to a 2nd-side communication channel used so far for inter-terminal real-time communication between the 2nd communication terminal and 1st communication terminal, but supplies a holding-tone signal to the 2nd-side communication channel to deliver the holding-tone signal to the 2nd communication terminal when the holding-tone transmission portion transmits the holding-tone signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a real-time communication system, a switching device, a real-time communication method, and a real-time communication program, and is suitable for application to, for example, outputting a hold tone with an IP telephone using VoIP technology.

  When a conventional IP telephone terminal on the extension side places a hold on the IP telephone terminal on the public network side, the operation is as shown in FIG.

  In FIG. 2, the IP telephone terminal 33 requesting the hold transmits a hold sound signal (real-time signal) HA 1, and the hold sound signal HA 1 is transmitted to the IP telephone terminal on the VoIP public network 32 side via the IP exchange (IP-PBX) 31. Up to 34. Thereby, the user who uses the IP telephone terminal 34 can listen to the hold sound corresponding to the hold sound signal HA1.

  However, when the operation as shown in FIG. 2 is performed, it is necessary to transmit the hold tone signal HA1, which is a real-time signal, on the route from the IP telephone terminals 33 to 34. Therefore, the bandwidth of the network such as the VoIP public network 32 In addition to consuming resources, the processing capability of the IP telephone terminal 33 that is the transmission source of the holding tone signal HA1, the processing capability of the IP switch 31 that relays the holding tone signal HA1, and the like are also consumed. Substantial use efficiency will fall and a big load will be applied to an apparatus.

  In addition, in the IP exchange 31, for relaying the music on hold signal HA1, from the extension side RTP (real-time transport protocol) receiving thread 36, which is an extension side component, to the public network side RTP, which is a component on the public network side. Many resources that reach the reception thread 37 are consumed. Since the load is easily concentrated on the IP switch 31, there is a great need to reduce the load on the IP switch 31.

  In addition, holding may be performed simultaneously for a plurality of IP telephone terminals. For example, in the example of FIG. 2, the IP telephone terminal 33 transmits a holding tone signal (HA2) to the IP telephone terminal 35 simultaneously with the IP telephone terminal 34. In this case, twice the resources are consumed according to the two holding tone signals HA1 and HA2, and the IP telephone terminal 33 and the IP exchange 31 have a large load that is twice as much as when only the holding tone signal HA1 is transmitted. It will take.

  In order to solve this problem, in the first aspect of the present invention, the third communication terminal is in a state in which a call is set between the first communication terminal and the second communication terminal and real-time communication is performed between the terminals. Since the second communication terminal arrives at the second communication terminal, the second communication terminal instructs the first communication terminal to hold, temporarily interrupts the real-time communication between the terminals, and is held until the hold is released. In a real-time communication system that outputs a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication via the user interface of the first communication terminal, (1) An exchange device for relaying the exchanged call control signal and the inter-terminal real-time signal between the first interface side and the second interface side; (2) a first-side real-time signal receiver that is activated by receiving an inter-terminal real-time signal on the first interface side; and (3) an inter-terminal real-time signal is received on the second interface side. A second-side real-time signal receiver that is activated by this, and (4) provided in the switching apparatus for each second-side communication channel set on the second interface side for the real-time communication between the terminals, A state in which the display state is changed from the previous hold sound non-transmission state to the hold sound transmission state by receiving a hold instruction signal instructing the hold from the second communication terminal arranged on the first interface side. (5) The state displayed on the state display unit is periodically inspected, and the state displayed as a result of the inspection is the holding tone transmission state. For example, when the on-hold sound transmission unit generates and transmits the on-hold sound signal, and (6) the on-hold real-time signal received from the second communication terminal Until the second side communication channel used for real-time communication between the second communication terminal and the first communication terminal is not supplied to the second side communication channel, the hold tone signal is supplied to the second side communication channel. And a switch unit for delivering the hold sound signal to the second communication terminal.

  In the second aspect of the present invention, the third communication terminal to the second communication terminal in a state in which a call is set between the first communication terminal and the second communication terminal and real-time communication between the terminals is performed. Since the second communication terminal instructed the first communication terminal to hold and temporarily interrupted the inter-terminal real-time communication and released the hold, the second communication terminal is instructed to hold the first communication terminal. In a switching device that outputs a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication via the user interface of the communication terminal, (1) a call control signal exchanged between the terminals and First and second interfaces for transmitting and receiving the inter-terminal real-time signal; and (2) by receiving the inter-terminal real-time signal on the first interface side. A first side real-time signal receiver that operates, (3) a second side real-time signal receiver that is activated by receiving an inter-terminal real-time signal on the second interface side, and (4) an inter-terminal real-time communication Therefore, a hold instruction signal that is provided in the switching apparatus for each second communication channel set on the second interface side and instructs hold from the second communication terminal arranged on the first interface side The state display unit changes the state to be displayed from the previous hold sound non-transmission state to the hold sound transmission state by receiving (5), and periodically checks the state displayed on the state display unit. If, as a result of the inspection, the displayed state is the hold sound transmission state, the hold sound transmission unit that generates and transmits the hold sound signal; and (6) the hold sound transmission unit transmits the hold sound signal. When transmitted, the inter-terminal real-time signal received from the second communication terminal is the second-side communication channel that has been used for inter-terminal real-time communication between the second communication terminal and the first communication terminal. And a switch unit for delivering the hold sound signal to the second communication terminal by supplying the hold sound signal to the second communication channel.

  Further, in the third aspect of the present invention, the third communication terminal to the second communication terminal in a state in which a call is set between the first communication terminal and the second communication terminal and real-time communication between the terminals is performed. Since the second communication terminal instructed the first communication terminal to hold and temporarily interrupted the inter-terminal real-time communication and released the hold, the second communication terminal is instructed to hold the first communication terminal. In a real-time communication method for outputting a predetermined hold sound signal instead of a real-time signal between terminals used for real-time communication between terminals via a user interface of a communication terminal, (1) exchange devices are exchanged between terminals. When the call control signal and the inter-terminal real-time signal are relayed between the first interface side and the second interface side, (2) The one-side real-time signal receiving unit is activated by receiving the inter-terminal real-time signal on the first interface side, and (3) the second-side real-time signal receiving unit on the second interface side (4) for real-time communication between the terminals, a status display unit provided in the switching apparatus for each second communication channel set on the second interface side, By receiving a hold instruction signal for instructing hold from the second communication terminal arranged on the first interface side, the display state is changed from the hold sound non-transmission state so far to the hold sound transmission state, (5) The holding sound signal transmitting unit periodically inspects the state displayed on the state display unit, and the state displayed as a result of the inspection is the holding sound transmission state If the hold sound signal is generated and transmitted, and (6) the hold sound transmission unit transmits the hold sound signal, the switch unit transmits the inter-terminal real-time signal received from the second communication terminal, The hold tone signal is supplied to the second side communication channel without being supplied to the second side communication channel that has been used for the inter-terminal real-time communication between the second communication terminal and the first communication terminal until then. Thus, the hold sound signal is delivered to the second communication terminal.

  Furthermore, in the fourth aspect of the present invention, in a state where a call is set between the first communication terminal and the second communication terminal and real-time communication is performed between the terminals, the third communication terminal performs the second communication. Since the second communication terminal instructs the hold to the first communication terminal side due to the arrival at the terminal, the inter-terminal real-time communication is temporarily suspended, and the hold of the first one is suspended until the hold is released. (1) Call control exchanged between terminals in a real-time communication program for outputting a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication via the user interface of the communication terminal A switching device that relays the signal and the inter-terminal real-time signal between the first interface side and the second interface side. And (2) a first-side real-time signal reception function activated by receiving a real-time signal between terminals on the first interface side, and (3) receiving a real-time signal between terminals on the second interface side. A second-side real-time signal reception function activated by (4), provided for the second-side communication channel set on the second interface side for real-time communication between the terminals, provided in the switching apparatus, Status display for changing the display state from the previous hold sound non-transmission state to the hold sound transmission state by receiving a hold instruction signal instructing the hold from the second communication terminal arranged on the interface side of 1 (5) The state displayed in the state display function is periodically inspected, and the state displayed as a result of the inspection is transmitted as the hold sound. A hold sound transmission function for generating and transmitting the hold sound signal, and (6) an inter-terminal real-time signal received from the second communication terminal when the hold sound transmission function transmits the hold sound signal. Is not supplied to the second communication channel that has been used for the real-time communication between the second communication terminal and the first communication terminal until then, and the hold tone signal is transmitted to the second communication channel. By supplying, a switch function for delivering the hold sound signal to the second communication terminal is realized.

  According to the present invention, it is possible to save bandwidth resources, reduce the load on the processing capability of the device, and increase the substantial utilization efficiency of resources.

(A) Embodiment Hereinafter, an embodiment will be described by taking as an example the case where the real-time communication system, switching apparatus, real-time communication method, and real-time communication program according to the present invention are applied to a VoIP communication system using SIP as a call control protocol. To do.

(A-1) Configuration of Embodiment FIG. 3 shows an example of the overall configuration of the VoIP communication system 10 according to the present embodiment.

  In FIG. 3, the VoIP communication system 10 includes an IP-PBX 11, an extension network 12, a public network 13, and IP telephone terminals 14 to 16.

  Of these, the extension network 12 and the public network 12 are networks that use the IP protocol in the network layer of the OSI reference model. From the viewpoint of the IP-PBX 11, the extension network 12 corresponds to the local (extension) side, and the public network 13 corresponds to the outside line side.

  There may be a large number of IP telephone terminals on the extension network 12 and the public network 13. However, in order to simplify the explanation, in the illustrated example, one IP telephone terminal 14 exists on the extension network 12. Two IP telephone terminals 15 and 16 exist on the public network 13.

  The IP telephone terminals 14 to 16 are VoIP compatible telephone terminals. A personal computer or the like equipped with a speaker or a microphone and equipped with software for IP telephones can also be used as the IP telephone terminals 14 to 16. A combination of a VoIP gateway and a general telephone (non-VoIP telephone) can be used as these IP telephone terminals 14-16.

  Although the IP telephone terminals 14 to 16 may basically have the same function, the IP telephone terminal 14 on the extension network 12 side is a normal IP telephone terminal (for example, 15). , 16 etc.). When a normal IP telephone terminal issues a hold request, the above-described hold sound signal HA1 that is a real-time signal is transmitted. In this embodiment, the IP telephone terminal 14 is a control signal for requesting a hold. The transmission interval designation information TI1 that designates the transmission interval of the RTP packet up to that point need only be transmitted to the IP-PBX 11, and it is not necessary to continue to transmit a real-time signal corresponding to the hold tone signal HA1 or the like.

  If SIP is used as the call control protocol, a re-INVITE message, which is one of SIP messages, can be used as the control signal. It is a SIP-UA (user agent) installed in the IP telephone terminal 14 that executes transmission / reception of such SIP messages on the IP telephone terminal 14 side.

  The IP telephone terminal 14 is used by the user U4, the IP telephone terminal 15 is used by the user U5, and the IP telephone terminal 16 is used by the user U6.

  In the following, since the user U4 using the IP telephone terminal 14 is receiving a call from the IP telephone terminal 16 to the IP telephone terminal 14 while talking to the user U5 using the IP telephone terminal 15, the user U4 makes the IP telephone terminal 14 An explanation will be given by taking as an example a case where an operation is requested to place a hold on the IP telephone terminal 15 side and a call with the user U6 using the IP telephone terminal 16 is started. In this case, it is necessary for the user U5 of the IP telephone terminal 15 to listen to the hold sound. The hold tone is transmitted as an RTP packet in the same manner as the call between the users U4 and U5, but the RTP packet corresponding to the hold tone (corresponding to the hold tone signal) is transmitted from the IP-PBX 11 (not the IP telephone terminal 14). Is.

  In this case, the packet interval (RTP packet transmission interval) when the RTP packet is transmitted from the IP telephone terminal 14 to the IP telephone terminal 15 for the call between the users U4 and U5 until the hold is requested, It is also necessary to maintain the transmission of the RTP packet for allowing the user U5 to listen to the hold tone. Therefore, as described above, the transmission interval designation information TI1 for designating the transmission interval of the RTP packet is transmitted from the IP telephone terminal 14 to the IP-PBX 11.

  The internal configuration of the IP-PBX 11 may be as shown in FIG.

(A-1-1) Internal Configuration Example of IP-PBX In FIG. 1, the IP-PBX 11 includes communication units 20 and 22, a control unit 21, a storage unit 23, an extension voice receiving unit 24, and a public side. A holding sound transmission unit 25, a media switch unit 26, a holding sound transmission state flag unit 27, and a transmission interval processing unit 28 are provided.

  Most of the functions of these components 20 to 28 can be realized in software in a normal implementation.

  The communication unit 20 is a part connected to the extension network 12, and the communication unit 22 is a part connected to the public network 13. A protocol corresponding to a layer below the network layer of the OSI reference model may be processed by the communication units 20 and 22.

  The control unit 21 corresponds to a CPU (central processing unit) of the IP-PBX 11 in terms of hardware, and may correspond to a main part of an OS (operating system) in terms of software.

  The storage unit 21 corresponds to a nonvolatile storage unit (for example, a ROM or a hard disk) and a volatile storage unit (for example, a RAM) in terms of hardware, and corresponds to various files in terms of software. It is. A function realized by software such as the OS can be one of such files in the form of a program file, a data file, or the like. Also, an internal buffer B1, a cutout buffer B2, and a transmission buffer B3, which will be described later, can be realized in the form of a storage area secured on the RAM.

  The transmission interval processing unit 28 is a part that receives the transmission interval designation information TI1 described above, and transmits the RTP packet corresponding to the holding tone by the transmission interval corresponding to the transmission interval designation information TI1. Specifically, the RTP packet transmission interval is, for example, 20 msec to 120 msec in time. If the data amount for 10 msec is 80 bytes, the data amount corresponds to 160 bytes to 960 bytes. As an example, when the transmission interval specified by the transmission interval specification information TI1 is 20 msec (160 bytes), the transmission interval processing unit 28 generates an RTP packet having a payload portion (data portion) of 160 bytes. Will be sent.

  The public-side hold sound transmitter 25 generates and transmits an RTP packet corresponding to this hold sound.

  The extension voice receiving unit 24 is a part that receives RTP packets via the extension network 12 and the communication unit 20. The extension voice receiving unit 24 has been conventionally installed in the IP-PBX and is configured to be triggered by the reception of an RTP packet containing voice data (for example, corresponding to the voice uttered by the user U4). Has been.

  The same components as the extension voice receiving unit 24 are conventionally provided on the public network 13 side. This is a public voice receiving unit 45 (see FIG. 4) that is activated by receiving a RTP packet from the communication unit 22 via the public network 13 as a trigger.

  The extension voice receiving unit 24 and the public voice receiving unit 45 are configured to dynamically end the sleep state up to that point and start up, triggered by the reception of the RTP packet. Although it is desirable to reuse existing assets (in this case, 24 and 45) from the viewpoint of reducing the cost of product development, the transmission of music on hold from the IP-PBX 11 required in this embodiment will be described later. Therefore, it is difficult to implement by using the extension voice receiving unit 24 and the public voice receiving unit 45.

  Therefore, in the present embodiment, the public-side hold sound transmission unit 25 is provided separately from the extension voice reception unit 24 and the public voice reception unit 45.

  The public-side holding sound transmission unit 25 is a part that is periodically activated to inspect the state of the holding sound transmission state flag unit 27 and execute an operation according to the inspection result. As a result of the examination, if the state of the on-hold sound transmission state flag unit 27 is a value that designates transmission of the on-hold sound signal (here, “1”), the public-side on-hold sound transmitting unit 25 determines that the on-hold music signal transmission unit 25 Is generated and transmitted, and conversely, if it is a value designating non-transmission of the holding sound signal (here, “0”), the generation or transmission of the holding sound signal is not performed.

  The public-side on-hold tone transmission unit 25 is a component for transmitting a hold-on tone signal to the public network 13 side instead of the IP telephone terminal 14 existing on the extension network 12 side. Instead of an IP telephone terminal (for example, 15) existing on the public network 13 side, a component for transmitting a holding tone signal to the extension network 12 side may be provided in the IP-PBX 11. That is the public-side holding sound transmitter 43B shown in FIG.

  There may be various methods for realizing regular activation of the public-side holding tone transmission unit 25. For example, it may be activated periodically by using a timer of the OS.

  The media switch unit 26 allows data (voice data) received in the RTP packet from the extension network 12 (communication unit 20) side to flow to the public network 13 (communication unit 22) side. This is a switch that functions when data (voice data) received in the RTP packet from the side is sent to the extension network 12 side.

  As already described, the hold tone transmission state flag section 27 displays a value (“1”) that designates transmission of a hold tone signal or a value (“0”) that designates non-transmission of a hold tone signal. It is a flag to do. Within the IP-PBX 11, the value of the flag section 27 is determined by supplying an RTP packet containing voice data to a corresponding channel on the public side (channel connected to the IP telephone terminal 15) or holding music. It has a meaning of specifying whether to supply an RTP packet containing a signal.

  FIG. 4 shows a configuration example when a part of the IP-PBX 11 is realized by software. As already explained, there are also components not shown in FIG. 1 in FIG.

  In FIG. 4, the IP-PBX 11 includes an RTP control unit 41, data 42, threads 43, 44 and 45, and a socket interface 46.

  Of these, the RTP control unit 41 is a part that controls relay of real-time voice data exchanged between IP telephone terminals (for example, between 14 and 15).

  The data 42 includes music on hold data 42A, common data 42, and 42C for channel management.

  The hold sound data 42A is data related to the hold sound signal, such as data that is the basis of the hold sound signal. The hold sound data file F1 shown in FIG. 8 corresponds to the hold sound data 42A. The common data 42B is data that can be used by each component in the IP-PBX 11. The channel management data 42C is data for managing channels on the extension network 12 side and the public network 13 side.

  The thread (task) 43 includes two threads 43A and 43B. Among these, the public-side holding sound transmission unit 43B corresponds to the public-side holding sound transmission unit 25, and thus detailed description thereof is omitted. The function of the extension side on-hold tone transmission unit 43A is as described above.

  Further, the extension voice receiving unit 44 corresponds to the extension voice receiving unit 24, and a detailed description thereof will be omitted. The function of the public voice receiver 45 is also as already described.

  The socket interface 46 provides a socket that is a function positioned in the transport layer or the session layer in the OSI reference model. A socket is a component that functions as a logical communication terminal for exchanging information between a communication application (here, corresponding to 43A, 43B, etc.) positioned higher in the OSI reference model and a lower communication protocol. is there. The channel (CH 21 and the like which will be described later is also set in this way) is set between the socket in the IP-PBX 11 and the socket in the opposite communication device (for example, the IP telephone terminal 15). The

  The socket interface 46 includes socket descriptors 46A to 46D. The socket descriptor describes attribute information of each socket.

  Hereinafter, the operation of the present embodiment having the above-described configuration will be described with reference to FIGS.

  FIGS. 5 and 6 show processing using the music-on-hold transmission status flag unit 27, and FIG. 7 is a schematic diagram showing a method for realizing transmission according to the transmission interval specified by the transmission interval specification information TI1. is there.

  FIG. 8 is a schematic diagram showing how the music on hold data is read from the music on hold data file F1 into the internal buffer B1, and FIGS. 9 and 10 are schematic diagrams showing the generation operation of the RTP packet corresponding to the music on hold. . FIG. 11 is a schematic diagram showing the overall operation of the VoIP communication system 10.

  Also here, as described above, since the user U4 using the IP telephone terminal 14 is talking to the user U5 using the IP telephone terminal 15, the user U4 receives the call from the IP telephone terminal 16 to the IP telephone terminal 14. The operation will be described by taking as an example a case in which the IP phone terminal 14 is operated to request a hold on the IP phone terminal 15 side and a call with the user U6 using the IP phone terminal 16 is started.

(A-2) Operation of Embodiment Initially, the user U4 using the IP telephone terminal 14 is talking with the user U5 using the IP telephone terminal 15 by VoIP communication via the IP-PBX 11. In this call, as shown in FIG. 11, the voice data AC5 corresponding to the content spoken by the user U5 is received by the public voice receiver 45 of the IP-PBX 11, and the voice data AC4 corresponding to the content spoken by the user U4 is The extension voice receiving unit 24 (44) of the IP-PBX 11 has received it.

  At this time, in the IP-PBX 11, as shown in FIG. 11 and FIG. 5, the channel CH11 which is one of the extension side (extension network 12 side) channels and the public side (public network 13 side) channel 1 One channel CH21 is assumed to be used. That is, the voice data indicating the content of the voice uttered by the user U4 reaches the extension voice receiving unit 24 in the IP-PBX 11 via the channel CH11 and is transmitted to the public network 13 via the channel CH21.

  At this time, the hold sound transmission state flag unit 27 shown in FIG. 5 maintains “0” that designates non-transmission of the hold sound signal.

  The extension voice receiving unit 24 (44), which is a thread, is activated when an RTP packet containing the voice data is received from the communication unit 20, and when activated, the extension voice receiving unit 24 (44) Check the value. Here, since the value of the holding tone transmission status flag section 27 is “0”, it is understood that the extension voice receiving section 24 does not need to pass the right to use the channel CH21 to the public-side holding tone transmitting section 25. The RTP packet containing the voice data AC4 is sent from the channel CH21 to the public network 13. Since a transport layer header (usually a UDP header) and an IP header are added to the RTP packet before being sent to the public network 13, it is transmitted through the public network 13 in the form of an IP packet, and the IP telephone terminal 15 Delivered to. Thereby, the voice uttered by the user U4 is heard by the user U5. The process for delivering the voice uttered by the user U5 to the user U4 is omitted here.

  The public-side hold sound transmission unit 25 (43B) is periodically activated by using an OS timer or the like, and checks the value of the hold sound transmission state flag unit 27 every time it is activated. As long as the value of the on-hold tone transmission state flag section 27 maintains “0” that specifies non-transmission of the on-hold tone signal, the public-side hold tone transmitting section 25 simply repeats this operation.

  Thus, when a call between the users U4 and U5 is made, the IP phone terminal 16 receives the call to the IP phone terminal 14, and the user U4 interrupts the call with the user U5 and makes a call with the user U6. Assume that a hold request operation is performed on the IP telephone terminal 14. The content of this operation may differ depending on the configuration of the user interface of the IP telephone terminal 14, but may be, for example, pressing a predetermined “hold” button.

  When this operation is detected, the IP telephone terminal 14 transmits the re-INVITE message to request suspension, and transmits the transmission interval designation information TI1.

  In the IP-PBX 11 that has received the re-INVITE message, the value of the on-hold tone transmission status flag section 27 is changed from “0” to “1” that specifies transmission of the on-hold tone signal.

  As a result of the inspection, the internal voice receiving unit 24 that has recognized that the value of the holding tone signal transmission state flag unit 27 is “1” passes the right to use the channel CH 21 to the public side holding tone transmitting unit 25. Therefore, the voice data received from the channel CH11 on the extension network 12 side is discarded. At this time, the voice data AC4 has already changed to the content that the user U4 has spoken to the user U6 using the IP telephone terminal 16. By the discarding, it is possible to prevent the user U5 from listening to the content of the user U4 speaking to the user U6.

  Depending on the internal configuration of the IP-PBX 11, there may be a configuration in which the audio data AC4 does not reach the internal audio receiving unit 24 at this time, but in the example of FIG. In this case, the voice data AC4 corresponding to the content uttered by the user U4 is routed to the IP telephone terminal 16 using a channel on the public network 13 side different from the channel CH21 through a route not shown in FIG. Will be delivered.

  On the other hand, as a result of the examination, the public-side hold sound transmission unit 25 that has recognized that the value of the hold sound signal transmission state flag unit 27 is “1” has passed the use right of the channel CH21 to itself. This is recognized, and the operation for generating and transmitting the music on hold signal is started. The generated hold sound signal is delivered to the IP telephone terminal 15 via the channel CH21, and the user U5 listens to the hold sound corresponding to the hold sound signal.

  The operation for generating the hold tone signal is as shown in FIGS.

  In order to generate the music on hold signal, it is first necessary to read the music on hold data stored in the music on hold data file F1 into the internal buffer B1 as shown in FIG. The music on hold data file F1 is one of data files stored in a nonvolatile storage means such as a ROM or a hard disk. The hold sound data stored in the file F1 is the basis of the hold sound signal.

  Since the size of the internal buffer B1 is the same as the size of the music on hold data stored in the file F1, all the music on hold data in the file F1 can be read into the internal buffer B1.

  Further, the process of FIG. 7 is executed almost simultaneously with the process of FIG.

  In FIG. 7, a channel-by-channel on-hold tone data table TB1 prepared for each public channel is used.

  The table TB1 includes a designated transmission interval and a transmission interval counter as data items.

  Among these, a value corresponding to the transmission interval designation information TI1 is registered in the designated transmission interval. In the example of FIG. 7, 2 is registered. This indicates a transmission interval according to time in units of 10 msec. That is, the transmission interval is 20 msec. As described above, if the data amount for 10 msec is 80 bytes, the transmission interval is 160 bytes as the data amount.

  In the transmission interval counter, a value to be decremented with 2 as an initial value is registered. Since the public-side holding tone transmission unit 25 is activated from the sleep state every 10 msec, it is necessary to ensure continuity of processing by the decremented value.

  The public-side hold sound transmitter 25 reads the hold sound data of 80 bytes (10 msec) from the beginning of the internal buffer B1, performs a predetermined conversion process, and stores the result of the conversion process in the cutout buffer B2. Write from. This conversion process is, for example, a process such as compression encoding, and is defined by a codec standard used in VoIP communication. Normally, when the conversion process is performed, the data size changes before and after the conversion process, but here it is assumed that the data size does not change for the sake of simplicity.

  Since the transmission interval is 20 msec, a storage area of 160 (= 80 × 20 ÷ 10) bytes is secured as the extraction buffer B2. When this cut-out buffer B2 is filled without excess or deficiency, one RTP packet is generated and transmitted.

  The RTP packet may be generated as it is from the contents of the cutout buffer B2, but here, as shown in FIGS. 9 and 10, a transmission buffer B3 having the same size as the cutout buffer B3 is prepared and converted. Is written in the cutout buffer B3, and when the cutout buffer B2 is filled, the data is transferred from the cutout buffer B3 to the transmission buffer B3, and the data read from the transmission buffer B3 is transmitted as the data portion of the RTP packet. Shall.

  In FIG. 9 and FIG. 10, the index data table TB2 prepared for each public-side channel has a holding tone index (holding tone INDEX) and a transmission interval as data items.

  Of these, the hold tone index registers a value that designates a position on the internal buffer B1. The initial value of this value is 0, which specifies the beginning of the internal buffer B1, but each time the music on hold data is read for each transmission interval and the conversion process is performed, the end of the read 160 bytes is added. The value is changed to the specified value.

  Therefore, when the transmission interval is 160 bytes, as shown in FIGS. 9 and 10, the value of the music on hold index changes as 0, 160, 320,. By using the music on hold index provided for each public channel and always reading from the beginning of the internal buffer B1, the user (here, U5) can always listen to the music on hold from the beginning. It becomes.

  By the way, when the size of the internal buffer B1 is 360 bytes, as shown in FIG. 10, after the music on hold index value becomes 320, there is a remainder of 40 (= 360−320) bytes at the end of the internal buffer B1. Arise. Since the music on hold data is time-sequential information, in order to allow the user U5 to listen to a natural music on hold without interruption, 360 bytes of music on hold data including this 40 bytes are continuously (without omission). It is necessary to generate the data part of the RTP packet so that the first 1 byte of 360 bytes is arranged immediately after the 1 byte located at the end of 360 bytes.

  For this reason, when the value of the holding tone index is 320, the last 40 bytes of the internal buffer B1 are read, and then the first 120 bytes are read to secure 160 (= 40 + 120) bytes at this time. When this time is over, the value of the music on hold index is 120. By repeating such an operation, the user U5 can be made to listen to the hold sound having the 360-byte period as one cycle for a necessary time.

  In the index data table TB2, a fixed value of 2 is registered to indicate the 160 bytes as the value of the transmission interval.

  When the call with the user U6 is finished and the user U4 performs an operation to cancel the hold on the IP telephone terminal 14, the fact is notified to the IP-PBX 11 via the extension network 12, and the value of the hold sound transmission state flag unit 27 Is changed from “1” to “0”. When this change is recognized by the public-side hold sound transmission unit 25, transmission of the RTP packet corresponding to the hold sound is stopped, and when the extension voice reception unit 24 recognizes this change, the discard of the voice data AC4 is stopped. As a result, the audio data AC4 is supplied to the channel CH21, and the conversation between the user U4 and the user U5 is resumed.

  Note that the IP telephone terminal 16 is received by receiving an IP telephone terminal 14 from a third user's IP telephone terminal (not shown) in a state where the RTP packet corresponding to the hold tone is delivered to the IP telephone terminal 15. May also need to be suspended. In such a case, the same operation as described above is only executed for the IP telephone terminal 16.

  In short, in the present embodiment, it is only necessary to transmit the re-INVITE message and the transmission interval designation information TI1 from the IP telephone terminal 14 that has requested the hold, and it is not necessary to continue to send a real-time signal corresponding to the hold tone signal. Therefore, the bandwidth resources of the extension network 12 and the processing capability of the IP telephone terminal 14 can be saved as compared with the conventional case.

  In addition, in the IP-PBX 11, when transmitting an RTP packet corresponding to a holding tone, the public side holding tone transmitting unit 25 is operating, but the extension voice receiving unit 24 is hardly required to operate. -The load on the processing capability of the PBX 11 can also be reduced.

(A-3) Effects of the Embodiment According to the present embodiment, it is possible to save bandwidth resources and reduce the load on the processing capability of the devices (14 and 11).

  If there is a margin in processing capacity or a margin in bandwidth resources due to the reduced load, this margin can be used to execute other important processes (including communication) or to speed up the processes already being executed. This increases the effective use of resources.

  In addition, since the present embodiment can be realized without changing the constituent elements (such as the extension voice receiving unit 24) that are conventionally mounted on the IP-PBX (IP-PBX product corresponding to 11), it has excellent feasibility. It can be said that

(B) Other Embodiments In the above embodiment, the case where the IP telephone terminal (15) disposed on the public network 13 side is suspended from the IP telephone terminal 14 disposed on the extension network 11 side has been described as an example. On the contrary, the present invention can also be applied to the case where the IP telephone terminal 14 arranged on the extension network 11 side is put on hold from the IP telephone terminal (15) arranged on the public network 13 side. .

  In addition, the present invention is not necessarily limited to between the extension network 11 and the public network 13, and the present invention can also be applied to a case where holding is performed between IP telephone terminals arranged in the extension network 11.

  Furthermore, in the above embodiment, the present invention is applied to IP-PBX, but the present invention may be applicable to communication apparatuses other than PBX.

  Note that the holding sound in the above embodiment may be replaced with other sounds. For example, it may be applicable to guidance (voice guidance), voice mail, voice talkie service, and the like.

  In the above description, sound is assumed. However, the present invention may be applicable to multimedia information other than sound. For example, in a videophone system or the like, there may be a configuration in which the other party visually observes the image for holding together with the holding sound or in place of the holding sound, and it is effective to apply the present invention to such a case. .

  Furthermore, it is generally considered that it is necessary to hold only for communication with a high real-time property, but the present invention is applied when there is a possibility of holding a communication even with low-real-time communication. can do.

  In the above embodiment, VoIP is taken as an example, but the present invention may be applied to other than VoIP. This is because the hold tone signal is transmitted from the telephone terminal requesting the hold in the PSTN.

  The communication protocol used in the above embodiment may be replaced with another communication protocol as necessary.

  For example, there is a possibility that the IPX protocol or the like may be used instead of the IP protocol, or a protocol other than SIP (for example, ITU-T recommendation H.323) may be used as the call control protocol.

  In the above description, most of the functions realized in hardware can be realized in software, and almost all the functions realized in software can be realized in hardware. .

It is the schematic which shows the example of an internal structure of IP-PBX used by embodiment. It is the schematic which shows the whole operation | movement of the conventional VoIP communication system. It is the schematic which shows the example of whole structure of the VoIP communication system concerning embodiment. It is the schematic which shows the structural example at the time of implement | achieving a part of IP-PBX used by embodiment by software. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment. It is operation | movement explanatory drawing which shows the operation example of embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... VoIP communication system, 11 ... IP-PBX, 12 ... Extension network, 13 ... Public network, 14-16 ... IP telephone terminal, 20, 22 ... Communication part, 21 ... Control part, 23 ... Memory | storage part, 24, 44 ... Extension voice receiving unit, 25 ... Public-side on-hold tone transmitting unit, 26 ... Media switch unit, 27 ... On-hold tone transmission state flag unit, 28 ... Transmission interval processing unit, 43A ... Extension side on-hold tone transmitting unit, 45 ... Public voice Receiving unit, 46... Socket interface.

Claims (6)

The second communication terminal because the third communication terminal received the second communication terminal in a state where a call was set up between the first communication terminal and the second communication terminal and real-time communication between the terminals was performed. Through the user interface of the first communication terminal that is on hold, until the first communication terminal side is instructed to hold, temporarily interrupt the real-time communication between the terminals, and release the hold. In the real-time communication system that outputs a predetermined holding sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication,
A switching device that relays a call control signal exchanged between terminals and a real-time signal between the terminals between the first interface side and the second interface side;
The exchange device
A first side real-time signal receiver that is activated by receiving an inter-terminal real-time signal on the first interface side;
A second side real-time signal receiver that is activated by receiving a real-time signal between terminals on the second interface side;
For the real-time communication between the terminals, each second communication channel set on the second interface side is provided in the switching apparatus and suspended from the second communication terminal arranged on the first interface side. A state display unit that changes the display state from the previous hold sound non-transmission state to the hold sound transmission state by receiving a hold instruction signal that instructs
The state displayed on the state display unit is periodically inspected, and as a result of the inspection, if the displayed state is the hold tone transmission state, the hold tone transmission unit that generates and transmits the hold tone signal;
When the hold sound transmission unit transmits a hold sound signal, the inter-terminal real-time signal received from the second communication terminal is the inter-terminal real-time communication between the second communication terminal and the first communication terminal until then. A switch unit for delivering the hold sound signal to the second communication terminal by supplying the hold sound signal to the second communication channel without supplying the second sound to the second communication channel. A real-time communication system characterized by that. The real-time communication system of claim 1.
The exchange device is
The transmission interval information specifying the transmission interval of the inter-terminal real-time signal that has been transmitted from the second communication terminal to the first communication terminal until then is received from the second communication terminal together with the hold instruction signal, A transmission interval information storage processing unit for storing each two-side communication channel;
The real-time communication system, wherein the holding tone signal transmitting unit transmits the holding tone signal at a transmission interval according to transmission interval information stored in the transmission interval information storage processing unit. The real-time communication system according to claim 2,
The holding tone signal transmitter is
In order to store the original hold sound signal that is the basis of the hold sound signal, an original hold sound storage buffer unit having a first size;
In order to store the converted hold sound signal obtained as a result of performing a predetermined conversion process on the original hold sound signal, the size is larger than the first size, and the second communication channel A post-conversion music on hold memory buffer unit having a second size corresponding to the size of the music on hold signal supplied to
A storage position index unit for designating a storage position on the original music on hold storage buffer unit for each second communication channel with predetermined storage position index information;
The original hold sound signal is read from the beginning of the original hold sound storage buffer unit by a predetermined read size smaller than the first size, and each time this read is performed, the tail end of the read original hold sound signal is read. When the storage position index information is changed to a value that specifies the storage position corresponding to the difference, and the difference between the tail of the original on-hold sound storage buffer unit and the storage position specified by the storage position index information is smaller than the read size, The original hold sound signal is read back to the storage position where the size from the start becomes the read size by returning to the start of the original hold sound storage buffer unit and adding to the difference again. Real-time communication system. The second communication terminal because the third communication terminal received the second communication terminal in a state where a call was set up between the first communication terminal and the second communication terminal and real-time communication between the terminals was performed. Through the user interface of the first communication terminal that is on hold, until the first communication terminal side is instructed to hold, temporarily interrupt the real-time communication between the terminals, and release the hold. In the exchange device that outputs a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication,
First and second interfaces for transmitting and receiving a call control signal exchanged between terminals and the real-time signal between the terminals;
A first side real-time signal receiver that is activated by receiving a real-time signal between terminals on the first interface side;
A second side real-time signal receiver that is activated by receiving a real-time signal between terminals on the second interface side;
For the real-time communication between the terminals, a second communication channel set on the second interface side is provided in the switching apparatus for each second communication channel, and is suspended from the second communication terminal arranged on the first interface side. A state display unit that changes the state to be displayed from the previous hold sound non-transmission state to the hold sound transmission state by receiving a hold instruction signal that instructs
The state displayed on the state display unit is periodically inspected, and as a result of the inspection, if the displayed state is the hold tone transmission state, the hold tone transmission unit that generates and transmits the hold tone signal;
When the hold sound transmission unit transmits a hold sound signal, the inter-terminal real-time signal received from the second communication terminal is the inter-terminal real-time communication between the second communication terminal and the first communication terminal until then. A switch unit for delivering the hold sound signal to the second communication terminal by supplying the hold sound signal to the second communication channel without supplying the second sound to the second communication channel. An exchange device characterized by that. The second communication terminal because the third communication terminal received the second communication terminal in a state where a call was set up between the first communication terminal and the second communication terminal and real-time communication between the terminals was performed. Through the user interface of the first communication terminal that is on hold, until the first communication terminal side is instructed to hold, temporarily interrupt the real-time communication between the terminals, and release the hold. In the real-time communication method for outputting a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication,
When the switching device relays a call control signal exchanged between terminals and the real-time signal between the terminals between the first interface side and the second interface side,
Inside the exchange,
The first side real-time signal receiving unit is activated by receiving an inter-terminal real-time signal on the first interface side,
The second side real-time signal receiving unit is activated by receiving an inter-terminal real-time signal on the second interface side,
For the real-time communication between the terminals, a status display unit provided in the switching apparatus for each second communication channel set on the second interface side is provided on the second interface side. By receiving a hold instruction signal instructing hold from the communication terminal of, the display state is changed from the hold sound non-transmission state until then to the hold sound transmission state,
The music on hold signal transmission unit periodically inspects the state displayed on the state display unit, and if the state displayed as a result of the inspection is the music on hold transmission state, the music on hold signal is generated and transmitted. ,
When the holding sound transmission unit transmits a holding sound signal, the switch unit transmits the inter-terminal real-time signal received from the second communication terminal between the second communication terminal and the first communication terminal. Delivering the hold sound signal to the second communication terminal by supplying the hold sound signal to the second communication channel without supplying it to the second communication channel used for the inter-terminal real-time communication. Real-time communication method characterized by this. The second communication terminal because the third communication terminal received the second communication terminal in a state where a call was set up between the first communication terminal and the second communication terminal and real-time communication between the terminals was performed. Through the user interface of the first communication terminal that is on hold, until the first communication terminal side is instructed to hold, temporarily interrupt the real-time communication between the terminals, and release the hold. In the real-time communication program for outputting a predetermined hold sound signal instead of the inter-terminal real-time signal used for the inter-terminal real-time communication,
A switching device that relays a call control signal exchanged between terminals and a real-time signal between the terminals between the first interface side and the second interface side;
In the exchange device, the computer
A first-side real-time signal reception function activated by receiving an inter-terminal real-time signal on the first interface side;
A second side real-time signal reception function activated by receiving a real-time signal between terminals on the second interface side;
For the real-time communication between the terminals, a second communication channel set on the second interface side is provided in the switching apparatus for each second communication channel, and is suspended from the second communication terminal arranged on the first interface side. A state display function for changing the display state from the previous hold sound non-transmission state to the hold sound transmission state by receiving a hold instruction signal instructing
The state displayed on the state display function is periodically inspected, and as a result of the inspection, if the displayed state is the hold sound transmission state, the hold sound transmission function for generating and transmitting the hold sound signal; and
When the hold tone transmission function transmits a hold tone signal, the inter-terminal real-time signal received from the second communication terminal is the inter-terminal real-time communication between the second communication terminal and the first communication terminal until then. A switch function for delivering the hold tone signal to the second communication terminal is realized by supplying the hold tone signal to the second communication channel without supplying the second hold channel to the second communication channel. A real-time communication program characterized by

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